Metastatic and/or unresectable (cT4b) disease Primary unresectable rectal cancer; a tumor is considered unresectable when invading adjacent organs and an en bloc resection will not achieve negative margins Patient must have unresectable disease Participants must have histologically confirmed melanoma that is metastatic or unresectable Have histologically confirmed unresectable or metastatic nonsquamous NSCLC and having received no prior systemic therapy for metastatic disease. Must have unresectable or inoperable stage IIIA or IIIB disease; subjects must be considered unresectable or inoperable based on the judgment of the treating physician Has cSCC that is either metastatic defined as disseminated disease, and/or unresectable disease that is not curable by surgery, radiation, or systemic therapy. Patients must have histologically confirmed MCM or ALM that is metastatic or unresectable Patients who have received prior immunotherapy for unresectable or metastatic disease SAFETY RUN-IN: Disease stage: unresectable metastatic disease Extent of disease\r\n* Unresectable Patients with unresectable disease are eligible Has received prior systemic treatment for unresectable or metastatic melanoma (except BRAF directed therapy). Unresectable or metastatic GIST Metastatic or unresectable solid tumor malignancy Patients must be considered unresectable or inoperable Subjects must have histologically confirmed solid malignancy that is metastatic or unresectable Unresectable disease. Patients with resectable disease may be enrolled after having refused surgery after a documented consultation with a surgeon. Patients may be potentially resectable or unresectable Cohort A: unresectable or metastatic melanoma Participants must not have had prior systemic anticancer therapy for unresectable or metastatic melanoma Tumor tissue from an unresectable or metastatic site of disease must be provided for biomarker analyses Patients who have histologically confirmed metastatic or unresectable GIST. Deemed to have unresectable disease by surgeon Metastatic and/or unresectable (cT4b) urothelial cancer. Measurable disease according to RECIST 1.1 within 30 days prior to registration. Unresectable thymoma or thymic carcinoma. Patients must have metastatic or unresectable disease, including those with HER2+ disease Participants must have histologically confirmed metastatic or unresectable melanoma Diagnosed with advanced (metastatic or unresectable) leiomyosarcoma or liposarcoma Has unresectable disease or is medically inoperable Unresectable metastases Have metastatic or unresectable sarcoma Patients with unresectable tumor Disease is termed unresectable or the patient refuses resection Metastatic or unresectable disease documented on diagnostic imaging studies Patients must be considered unresectable or inoperable Unresectable tumor Subject has unresectable disease; i.e. in the opinion of the surgical oncologist, all of the subject’s melanoma cannot be completely removed with a clear margin Patients whose tumors are deemed unresectable by clinical/imaging criteria Patient must have disease that is unresectable or borderline resectable with < 70% liver involvement by cancer The cancer must be unresectable The cancer must be unresectable Tumor progression during or after first-line treatment for advanced unresectable / metastatic ESCC Receipt of 2 or more prior systemic treatments for advanced/metastatic unresectable ESCC Patients must have histologically confirmed solid malignancy or lymphoma that is metastatic or unresectable Advanced (clinical stage T4b, unresectable) or metastatic disease Pathologically confirmed, advanced (unresectable or metastatic): Unresectable disease Histologically confirmed breast adenocarcinoma that is unresectable loco regional, or metastatic Has received prior systemic treatment for unresectable or metastatic melanoma (except BRAF directed therapy) Disease must be considered incurable; incurable is defined as metastatic disease or a local or regional recurrence in a previously irradiated site that is unresectable (or patient declines resection) Must have colorectal cancer with unresectable metastatic disease to the liver (unresectable unilobar or bilobar disease) who have disease progression in the liver with oxaliplatin or irinotecan based first line chemotherapy is unresectable or metastatic Subjects with recurrent (unresectable) or metastatic CRC: Treatment-naïve participants (no prior systemic anticancer therapy for unresectable or metastatic melanoma) Have received no prior systemic chemotherapy for advanced/unresectable (inoperable) or metastatic urothelial cancer. Subject has not been treated by systemic anticancer therapy for unresectable or metastatic melanoma Metastatic or unresectable cancer that expresses KIT as documented in the patient's pathology report. A diagnosis of metastatic or unresectable sarcoma Have histologically confirmed unresectable or metastatic melanoma having received no more than one prior systemic therapy for the metastatic disease (eg. ipilumamab and/or BRAF inhibitor); unresectable or metastatic smoking-associated NSCLC having received no more than one prior systemic therapy for the metastatic disease (eg standard of care chemotherapy, as appropriate); unresectable or metastatic transitional cell carcinoma of the bladder, urethra, ureter or renal pelvis having received no more than one prior systemic therapy for the metastatic disease. Histologic diagnosis of unresectable or metastatic BRAF V600 mutant melanoma Locally unresectable or metastatic carcinoid or pNET Participants must have unresectable or metastatic histologically confirmed intrahepatic cholangiocarcinoma Metastatic or unresectable disease documented on diagnostic imaging studies Must have unresectable or inoperable stage IIIA or IIIB disease. Patients are considered unresectable or inoperable based on the judgment of the treating physician Patients with unresectable melanoma Unresectable disease or subject refused surgery. Patients with unresectable or metastatic histologically confirmed sporadic or NF1 associated high grade MPNST Tumor tissue from an unresectable or metastatic site of disease for biomarker analyses Locally unresectable or metastatic carcinoid tumors Patients must have histologically confirmed malignancy that is metastatic or unresectable Unresectable or metastatic sporadic or NF1 associated high-grade MPNST Patients with unresectable lung metastases Patients with diffuse tumor throughout bladder that is deemed unresectable by surgeon Patients must have metastatic or unresectable disease Patients must have histologically confirmed adenocarcinoma of the small bowel or ampulla of Vater that is either unresectable or metastatic Unresectable disease or medically inoperable Patients must have unresectable disease as determined by the multidisciplinary evaluation or patient is not considered operable due to medical reasons Unresectable or metastatic disease Tumors clinically staged as unresectable disease Metastatic or recurrent disease that is deemed partially resectable or unresectable based on preoperative imaging A diagnosis of a metastatic or unresectable sarcoma Must have unresectable metastatic disease, and have tumor(s) present that is (are) evaluable by the RECIST, v1.1; may have spinal-associated metastases but must have concluded dexamethasone therapy and be evaluated by the Investigator to have stable CNS disease. Failed treatment with one regimen containing at least a platinum/fluoropyrimidine doublet for unresectable or metastatic disease.Treatment failure is defined as progression of disease (clinical or radiologic) during first line treatment for unresectable or metastatic disease or ? 6 months after last dose of first line treatment. Patients must have unresectable or metastatic disease Unresectable disease or subject refused surgery. Treatment with at least two prior systemic therapies for advanced (unresectable locoregional or metastatic) disease Subject must have unresectable or metastatic gastroesophageal adenocarcinoma. Subject with previously untreated unresectable or metastatic gastroesophageal adenocarcinoma. Unresectable disease or patient refused surgery. Tumor deemed unresectable or metastatic Disease must be considered unresectable at the time of preoperative evaluation NET and GIST tumors must be unresectable Surgically unresectable or metastatic disease. technically unresectable HGG Primary tumor deemed unresectable by hepatobiliary surgeon Advanced unresectable or metastatic disease Unresectable or metastatic SCCHN. Patients must have received at least one prior therapy for unresectable disease; patients with recurrence within 6 months of completion of neoadjuvant or adjuvant therapy may be considered as having received one prior therapy for unresectable disease Patients with metastatic or locally unresectable PDAC* (resectability is as defined by MSKCC pancreatic surgeon) Diagnosed with advanced (metastatic or unresectable) sarcoma Is unresectable or metastatic Diagnosis of unresectable or metastatic melanoma Current or pending participation in a clinical trial examining therapy for the\n treatment of any cancer (including unresectable or metastatic melanoma)